The Landau-Kleffner Syndrome is a very terrifying condition. It takes away a person's ability to make or understand speech.

First discovered in 1957 by William Landau and Frank Kleffner, the cases identified were all children, between three and thirteen. The children wouldn't respond to anything said to them even when they clearly saw the speaker. After a few months, the kids lost the ability to speak.

The Landau-Kleffner cases are tested for deafness and autism before they are diagnosed correctly. Some patients start to have seizures, though they only start after people stop speaking. The only way to be sure the syndrome is present is to do an electroencephalogram while the patient is sleeping to look for subclinical seizure activity in the brain.

For most, the treatment is anticonvulsant medication to stop the seizures. Corticosteroids help them regain speech activity, and some can rebuild speech activity on their own.

The frightening part of the syndrome is that it can relapse. It can literally wipe the off their brain again and again and while people retain all their memories and motor abilities, they lose out the words to express them.

[Neurology, ASHA.]